[TowerTalk] Rain static

[K4SAV]

When I lived in central Florida, running HF mobile CW, I sometimes would 
have high rain static and other times not. When the static was there, it 
was always proportional to vehicle speed.  I did experience an 
interesting phenomenon associated with lightning (Florida lightning is 
always interesting). When the rain static was not present, and when 
there was a lightning strike within a mile or so, I would get the crash 
in the receiver, and then a tremendous amount of static persisting for 
up to a minute or so, trailing off in amplitude.  This didn't happen 
every time, but often enough that it was noticable.  I have even heard 
it on 2 meters a couple of times. I always attributed this to rain 
particles getting charged and being picked up as I moved.  This static 
was also proportional to vehicle speed.  I never knew if my guess about 
what was happening was correct or not.  It just seemed like a logical 
explanation.

Just another ingredient for the soup.

Jerry, K4SAV


K8RI on Tower talk wrote:

>
>  
>
>>>Does anyone have any ideas of how I can solve this
>>>      
>>>
>>problem?
>>
>>Joe,
>>
>>There is some controversy or difference of opinion on this,
>>but my experience, everything I can measure or simulate, and
>>any data I get from other sources indicates the noise is
>>from corona discharge from sharp points in or around the
>>antenna. This corona discharge is caused by voltage gradient
>>between the earth and clouds around the antenna during
>>inclement weather.
>>
>>The other opinion (that I do not find evidence to support)
>>is that charged droplets or particles hit the antenna and
>>discharge, making noise.
>>    
>>
>
>I think you will find that precipitation static  is neither.
>It's basically the a charge building from many droplets, or snow flakes 
>removing electrons from the ungrounded elements, or wires.  The charge 
>builds to the point where it arcs over.
>
>Snow is particularly bad with this and the stronger the wind the more rapid 
>the charge.
>
>I've never had precipitation static from a grounded antenna.
>
>  
>
>>Regardless of the actual effect behind the noise grounding
>>the antenna or the fact it is a log periodic has nothing to
>>do with causing the problem or with sensitivity of the
>>antenna to noise. I have that problem with gamma matched
>>yagis just as much as with insulated elements. It occurs
>>with dc grounded elements the same as with floating
>>elements.
>>    
>>
>
>That has not been my experience.  However if there is an ungrounded antenna 
>near by, closeline, guy lines, or electric fence they will generate a spark 
>just like the old ignition systems with solid wires.  Those things could be 
>heard for hundreds of yards.
>  
>
>
>  
>
>>We spent weeks working on repeater and other communications
>>systems on tall buildings trying to eliminate that type of
>>noise. Lowering the antenna, making protruding antenna ends
>>blunter or more rounded or using insulated element tips,
>>installing something higher above the antenna to divert
>>charge to that other point and away from the antenna
>>elements, and eliminating sharp points on the tower and
>>antenna often help.
>>
>>    
>>
>
>The worst antenna I ever had for precipitation static was a 1/4 wave, ground 
>mounted vertical on 40 made out of 1 1/2" steel masting.  On a windy day 
>when it was snowing that thing would develop an arc across the end of a 
>PL-259. It wasn't straight across either. The arc would extend as much as a 
>half to three quarters of an ench forward from the tip of the connector and 
>it'd pop like a small firecracker.  It was a nice *thick* bright blue arc 
>about every 5 to 10 seconds.
>
>Roger Halstead (K8RI and ARRL 40 year Life Member)
>N833R - World's oldest Debonair CD-2
>www.rogerhalstead.com
>
>  
>
>>When I have that noise here I  switch to a lower antenna.
>>
>>73 Tom
>>
>>
>>_______________________________________________
>>
>>See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
>>Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
>>any questions and ask for Sherman, W2FLA.
>>
>>_______________________________________________
>>TowerTalk mailing list
>>TowerTalk at contesting.com
>>http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>    
>>
>_______________________________________________
>
>See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk at contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
>
>  
>